Telephone receiver of the watchcase type



Dec. 26,51'922. 1,439,785

, F. W. ANDREW. i .TELEPHoNEREcExvER 6F THr-:WATcHcAsr-z TYPE.

FILED APR. 20, f922..

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Patented Dec. 26, 1922.

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FREDERIICKW.V ANDREW, OF BROOKLYN, NEW YORK, ASSIGNOR TO EISEMANN MAGNETO CORPORATION, NRW YORK.

OF BROOKLYN, NEW YORK, A CORPORATION 0F TELEPHONE RECEIVER 0F THE WATCHCASE TYPE.

'Application filed `April 20, F1922. Serial No. 555,782. i

ers of the VVatchcase Type, of which the fol' lowing is a specification. y l

My invention 'relatesto telephone receivers of the so-calle'd watch-case type and its object is to provide an imp roved device of that kind in which efficiency iof operation is combined with eXtreme simplicity of construction.

though not limited to that field.

The advantages of'my invention will become clearfrom a detailed description of the accompanying drawings, in which-,-

Figure 1 sliows. aninterior vvie'w of thev shell or casing containing the magnet and coils- 4 .v

Fig. 2 is a transverse cross-section of the receiver shown inv Fig. 1, with the cap and diaphragm in position on the vcasing ;v

F ig. 3 is a detached'rear View of .the magnet and its coil-carrying pole pieces; and

Fig. 4 is a detached perspective view of one of-the pole pieces." The shell or casing 1 -is of shallow cylindrical 'form and is made of a suitable nonvmagnetic material, such as aluminum or the like. The back end of the casing is closed by a wall 2 and thefother or front end is open, so. as to receive the usual vibratory diaphragm 3 which is held in place by a cap 4 of insulating material. The cap 4 is screwed on to the casing' l by means of cooperating screw threads 5. The cap 4 is at the center provided with the usual sound opening 6.

`Within the shell or casing 1 is a permanent magnet M inthe form of a complete ring and shaped to fit snugly in the casing. The magnet M is usually made of hard magnet steel, sc as to retain its magnetism for a considerable period of time. has apair of soft iron pole pieces indicated as a whole by- P and P1.' These pole pieces are substantially L-shaped and each consists of a base portion 7 and a polar extension 8.

y The polar extensions 8 are adapted tol re- My newv telephone 'receiver..is particularly adapted for radiov work, al-v mg the combined advantages The magnet `ceive coils C and C1. These coils are connected` in series, as indicated at 9.

As illustrated in Fig. 2, the back wall 2 of the casing has a pair of holes 10, the magnet M has a` pieces P and in the base portion '7. Through the aligned holes 10, 11 and 12 pass metallic fastening members, such as screws or'bclts 13, which giir of holes 11', and the poleV 1 are provided with holes 12- are'insulated by insulating washers 14 and 1.5,and by insulating sleeves 16, or in any other suitable way.. The screws .or bolts 13 have each-a pair of nuts 17 and 18, which b ear against the washers 14 and 15, respectively, and by means of which the'magnetv and pole pieces P and P1 'are rigidly clamped -to the back wall of the casing. The coils C and' C1 are connected tothe inner ends of the fastening members 13 by wires 19 and 20 respectively. This'connection is preferably permanent and maybe secured soldering or in any other convenient manner. The outer ends of the fastening members 13 are 4provided with readily adjustable nuts 21 to permit clamping of electrical conductors between the nuts 17 and 21. In other words, the fastening members.

13 also act as binding postsv for the coils C and C1 to connectfthem in circuit. This dou- .ble function of the members 13 considerably simplifies the construction and correspondingly reduces the cost of manufacture.

It will be seen from the foregoing that I have provided a telephone receiver possessof simplicity ofvconstruction and eiiiciency of operation. The ring magnet M provides a divided magnetic circuit and has a greater magnetic length than a same-size magnet of the openring, structure. The construction is'so simple that there is very little mechanism in the shell or Casing, and it is well known that an empty sound box gives a better effect than one cluttered with structural parts. As the partsof my new telephone receiver are very few and easily made and assembled, the cost of manufacture is reduced to a minimum.

7What I claim is: LA telephone receiver of the watch-case type, comprising a non-magnetic circular shell or easing provided with a cap. and" diaphragm, a permanent ring magnet mounted in said casing and provided with tipe,

a pair of substantially L-shaped p'ole pieces, each pole piece having a base portion arranged between the magnet and back wall of the casing and a coil-carrying extension projecting substantially at right angles to the plane'oif the magnet, and insulated metallic fastening devices passing through said magnet and the base portions ot said pole pieces for securing -these parts to the back wal] ofwthe casing, said devices being constructed to serve as binding posts for the magnet coils.

2. A telephone receiver of the watch-case type, comprising a vn'on-n'iagnetic shell or casing provided with a cap and diaphragm, a permanent magnet within said casing and having pole pieces provided with coils,said pole pieces having' base portions arrange between the magnet and back wall of the casing, and a pair of insulated screws or bolts passing through said magnet and the base portions of said pole pieces for scour-- ing these parts to the back wall of the casing, said screws or bolts being constructed to serve as binding posts for said coils.

3. A telephone receiver of the watch-case comprising `a non-magnetic shell or casing provided with a'cap and diaphragm, a permanent magnet within said casing and having pole pieces provided with coils, said pole pieces being separate from the magnet and having each a portion in vContact with the magnet, and a pair of insulated screws or bolts passing through said magnet and the contact portions of said pole pieces for securing these parts to said casing,l said screws or bolts being constructed to serve as binding` posts for said coils.

4. A telephone receiver of the watch-case type, comprising a non-magnetic circular shell or casing provided with a cap and diaphragm, the closed back wall of said casing having a pair of holes, a permanent ring magnet in said casing. a pair of pole-pieces for said magnet, said pole-pieces consisting of polar extensions provided with coils and base portions extending between the magnet and back wall of the casing, said magnet and base portions having holes in alignment with said holes in the casing, and a pair of insulated screws or bolts passing .through said aligned holes for securing the vmagnet and pole-pieces to the back wall of the casing, said coils being connected to the inner.

ends of said screws or bolts and the outer ends of *said screws or bolts being adapted to act as bindingposts. 1

FRED RICK W. ANDREW. 

